here's abc's brian ross. >> reporter: increasingly, adam was so troubled he would not leave the house. and his mother, nancy, the last few months, told friends she was losing control of her 20-year-old son. >> it was just getting a little harder for her as time went on. >> reporter: nancy lanza was a regular here at this newtown bar and restaurant where the owners say she told them about her struggles with adam's behavioral problems for years. >> she home schooled him and everything. i knew he was on medication, but that's all i know. >> reporter: since elementary school at sandy hook through high school, adam was known by classmates as change, severely shy. >> he hated looking at your eyes for more than a couple seconds. he would always look down at his paper or whatever he was doing. >> reporter: a former babysitter says he was told by the mother to never leave adam alone. >> never go to the bathroom or turn your back on him at any time. >> reporter: the former school security director, who became close to adam when he was in the high school tech club, said adam had several disorder